Locking mechanism having key operation on two sides

ABSTRACT

A locking mechanism operable by a key from either of two sides thereof is disclosed having two cylindrical housings operatively connected by a bridge whereby a U-shaped space is formed between the cylindrical housings. Each of the cylindrical housings contains a key plug of the tumbler type. The key plugs extend into the U-shaped space where fingers are mounted thereon for operation of a bolt element. The bolt element is slideably mounted between a pair of parallel assembly plates which have aligned apertures therein of the same configuration as one of the cylindrical housings so that the cylindrical housing may be passed through said apertures to position the U-shaped space between the plates. The bolt element is formed of a pair of parallel bolt plates operatively connected together at its internal end and having a solid portion with a strike camming surface connected at its opposite end for cooperation with a door frame. The solid portion is connected to the bolt plates of the bolt element on each side thereof by oppositely and symetrically positioned screws to enable the solid portion to be mounted to the bolt plates with its strike camming surface facing either direction. A pin structured keeper is mounted for movement transverse to the sliding movement of said bolt element for insertion into a bore in the solid portion of the bolt element and thereby maintain the bolt element in a retracted position.

United States atent 1 Prahl 1 Sept. 18, 1973 LOCKING MECHANISM HAVING KEY OPERATION ON TWO SIDES [76] Inventor: Herman Prahl, 48-38 58th Ln.,

Woodside, N.Y. 11377 [22] Filed: Sept. 22, 1971 [21] Appl. No.: 182,590

[52] US. Cl 70/143, 70/156, 70/380,

70/DIG. 60, 292/150, 292/l69.l4 [51] Int. Cl E0511 63/14 [58] Field of Search 70/134, 143, 150,

70/152, 156, 373, 379 R, 379 A, 380, 462, DIG. 60; 292/2, 137, 150, 169.22, 207, 244

Primary Examiner-Albert G. Craig, Jr. Attorney-Harvey Zeller [57] ABSTRACT A locking mechanism operable by a key from either of two sides thereof is disclosed having two cylindrical housings operatively connected by a bridge whereby a U-shaped space is formed between the cylindrical housings. Each of the cylindrical housings contains a key plug of the tumbler type. The key plugs extend into the U-shaped space where fingers are mounted thereon for operation of a bolt element. The bolt element is slideably mounted between a pair of parallel assembly plates which have aligned apertures therein of the same configuration as one of the cylindrical housings so that the cylindrical housing may be passed through said apertures to position the U-shaped space between the plates. The bolt element is formed of a pair of parallel bolt plates operatively connected together at its internal end and having a solid portion with a strike camming surface connected at its opposite end for cooperation with a door frame. The solid portion is connected to the bolt plates of the bolt element on each side thereof by oppositely and symetrically positioned screws to enable the solid portion to be mounted to the bolt plates with its strike camming surface facing either direction. A pin structured keeper is mounted for movement transverse to the sliding movement of said bolt element for insertion into a bore in the solid portion of the bolt element and thereby maintain the bolt element in a retracted position.

12 Claims, 7 Drawing Figures Patented Sept. 18, 1973 2 Sheets-Sheet l l LOCKING MECHANISM HAVING KEY OPERATION ON TWO SIDES BACKGROUND OF THE INVENTION both sides of a door. The present invention is particu- 1 larly suitable for incorporation therein of the cylinder lock described in applicant's pending United States Patent Application Ser. No. 175,468, filed Aug. 27, 1971, titled Cylinder Lock Usable as Mortise or Rim Lock and Having Alarm.

In numerous situations it is necessary to employ locks on doors which are key operated from both sides of the door. In such situations it is particularly desirable to employ a locking mechanism which is of a unitary structure so that it may be manufactured for installation in the locking assembly of the door in one piece thus insuring cooperative relationship of the two key operated mechanisms and facilitating the use of the same key on each side of the door. Such unitary locking mechanisms have heretofore, however, been unacceptable in that the insertion of the key in one side of the lock to operate the bolt element has been possible only when there is no key inserted in the opposite side of the locking mechanism.

It is therefore one object of the present invention to provide a locking mechanism which may be unitarily inserted into a door for cooperation with a bolt element and which is operable by a key on either side of the door regardless of whether or not a key is positioned in the key slot on the opposite side of the door.

In situations where locks of the above type have been required, it is frequently necessary to provide only a minimum amount of protection on one side of the door and to provide a maximum amount of protection on the opposite side of the door. It is therefore another object of the present invention to provide a locking mechanism operable by the same key on either side of the door where one side is provided with the security of a plurality of rows of tumblers for maximum security and the other side is provided with a single row of tumblers for minimum security.

As may be expected doors requiring the use of locks having keys on each side thereof may at random be swingable alternatively in either an inward or outward direction. Furthermore, it may be desirable to have such doors swing closed and be locked without the use of a key. Thus, it is desirable to have a bolt element with a reversable strike camming surface. It is therefore another object of the present invention to provide such a bolt element particularly usable with a locking mechanism key operated from two sides.

Also,'as may be expected in situations requiring the use of locking mechanisms key operable on both sides of the door, it is frequently desirable to havemeans for retaining the bolt element in a retracted position to eliminate the need to use a key at particular times. It

is therefore an additional object of the present invention to provide a simple keeper mechanism for retaining bolt normally spring biased to latching position in a retracted position.

SUMMARY OF THE INVENTION The above objects are accomplished by means of the present invention which briefly includes two cylindrical housings operatively connected by a bridge whereby a U-shaped space is formed between the housings. The housings are of the tumbler type and house corresponding key plugs. The key plugs extend into the U-shaped space and have individual finger means respectively 0 connecced thereto in such space for operation of a single bolt element. The bolt element is mounted between a pair of plates to be housed in the door adjacent its edge. The plates have aligned apertures therein of the same configuration as one of the cylindrical housings so that the cylindrical housing may be passed through said apertures to position the U-shaped space between the plates. The bolt element is provided with a reversable beveled strike camming surface and a keeper mechanism is provided for retaining the bolt element in a retracted position when desired.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an exploded perspective view of the locking assembly of the instant invention;

FIG. 2 is a cross sectional view of the locking mechanism of the instant invention taken along lines 2-2 of FIG. 1;

FIG. 3a is a plane view of the fastening segment of the finger means used in the locking mechanism of the instant invention;

FIG. 3b is a plane view of a development segment of the finger means used in the locking mechanism of the instant invention;

FIG. 30 is a partial perspective view showing the end of a key plug used in the locking mechanism of the instant invention;

FIG. 4 is an exploded perspective view of the bolt element employed in the locking assembly of the instant invention; and

FIG. 5 is a partial perspective view of an alternate embodiment of the locking mechanism of the instant invention employed as a rim lock.

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings and initially to FIG. 1 there is shown a locking assembly consisting generally of a two sided key operated locking mechanism including a pair of cylindrical housings l0 and 11 for housing key plugs 12 and 13, respectively, of the tumbler type, a bridging means 14 and bolt actuating or finger means 15 and 16; a bolt element generally designated as 17; keeper mechanism generally designated I8; a knob rotatable bolt actuating finger l9; and a frame including a pair of parallel spaced assembly plates 20 and 21 and an end plate 2.2.

Theslocking mechanism shown in broken portions in FIG. Land in cross section in FIG. 2 includes a'pair of cylinder tumbler type lock structures 10 and II operatively connected by bridge 14. The cylinder lock structure designated 10 is of the multiple tumbler row type described in applicant's above referred to pending U. S. patent application and the disclosure of that application is incorporated herein. Hence, further description of cylinder lock structure 10 is not required.

Cylinder lock structure I] has a key hole shape cross-sectional configuration to accommodate a single row of tumbler pins. Key plug 13, however, has the same key slot configuration as that of the key slot in key plug 12 so that the same key may be used on each side of the locking mechanism. The internal tumbler mechanisms are well known and thus no description thereof is necessary.

Cylinder housing 11 has an integral extension thereof designated 14 which has an upstanding portion 23 of the same key hole configuration as housing 11. Upstanding portion 23 has a cylindrical bore 23a therethrough permitting key plug 12 of cylinder housing to pass through said upstanding portion 23. Thus, extension 14 serves as a connecting breidge between cylinder housings 10 and 11 and provides a U-shaped space 24 between housings 10 and 11.

Fingers 15 and 16 are rigidly secured to key plugs 12 and 13 respectively in U-shaped space 24 for operation of bolt element 17 to be described hereinafter.

The locking mechanism is operatively mounted in a door by means of parallel plates 20 and 21 and end plate 22. Plates 20 and 21 have apertures 101 and 102, respectively, having the same key hole shape as cylinder housing 11 permitting the locking mechanism to be slid into position with the U-shaped space 24 and fingers 15 and 16 between plates 20 and 21. Normally, finger 15 is oriented at approximately 45 to vertical when the key is not in key plug 12 so that the locking mechanism may not be removed from the door without usage of a key.

A bracket 103 is provided with a hole 104 therethrough in alignment with threaded bore 105 in bridge 14. Set screw 106 passes through hole 107 in end plate 22 also aligned with hole 104 and bore 105 to assist plates 20 and 21 in orienting the locking mechanism.

I-Ioles 108 are provided in plate 20 in alignment with threaded bores in the interior face of housing 10 to permit housing 10 to be screw fastened to plate 20 to prevent its rotation with respect to the plate.

Finger 15 is provided as a solid element and is secured to key plug 12 by means of screws 25 and 26. Finger 15 is secured to key plug 12 prior to the insertion of key plug 13 into cylinder housing 11.

Finger 16 is developed by a plurality of segments 27, 28 and 29 which are mounted on the end of key plug 13. Referring specifically to FIGS. 3a, 3b and 30, segments 27 and 28 shown in FIG. 3a have apertures therein and segment 29 shown in FIG. 3b as an aperture 31 therein angularly offset from the apertures 30 of segments 27 and 28. Aperture 31 of segment 29 is similar to aperture 30 and additionally has arcuate cutouts located therein at 32 and 33. The end of key plug 13 is formed with an extension 34 thereon having the same size and configuration as aperture 30 and having a groove therein at 35 corresponding to arcuate cutouts 32 and 33 of segment 29. Each of the segments 27, 28 and 29 additionally have holes therein at 36. Thus, finger 16 is developed by placing segment 29 on the end of key plug 13 in groove 35 and rotating it about the axis of key plug 13 the angular distance by which its aperture 31 is offset from apertures 30 of segments 27 and 28 and then placing segments 27 and 28 on end 34 of key plug 13 so that holes 36 in each of the segments are in alignment. The segments may then be riveted together by a rivet passing through holes 36. Thus, finger 16 is secured to key plug 13.

Bolt element 17 shown in exploded perspective view in FIG. 4 consists of a pair of parallei bolt plates 40 and 41. Each of the plates is identical and has apertures 42a and 42b elongated slot 43, apertures 44a, 44b, 44c and 44d and notched portions 45a and 45b located between plates 40 and 41. Secured to these plates is a solid portion 46 having a generally trapezoidal shape with two parallel sides 47 and 48, a perpendicular side 49 and a beveled strike camming surface 50. Parallel sides 47 and 48 have inwardly stepped portions 51 and 52 respectively having symetrically located threaded bores 53 and 54 therein (only those in stepped portion 51 are shown in FIG. 4) which align with holes 4211 and 42b of plates 40 and 41 whereby said solid portion 47 is secured to said plates 40 and 41 by screws 55a and 55b (only two of which are shown in FIG. 4). Thus, solid portion 47 may be located between plates 40 and 41 with strike camming surface 50 facing either of two directions, as required by the direction in which the door swings.

Also located between plates 40 and 41 is spring biased member 56 having a tab 57 thereon, a T-shaped section 58 and a base 59. Member 56 is secured to plates 40 and 41 by bracket 60 having projections 61a, 61b, 61c and 61d on each side thereof which mate with apertures 44a, 44b, 44c and 44d of plates 40 and 41. Recess 62 is provided in bracket 60 to permit the stem of T-shaped section 58 of member 56 to move therein. Springs 630 and 63b are provided within bracket 60 in sections 64a and 64b respectively to normally bias member 56 downwardly whereby base 59 is situated in the space between notches 45b of plates 40 and 41 and whereby tab 57 is situated in the space between elongated slots 43 in plates 40 and 41. Bolt element 17 is slideably mounted between plates 20 and 21, by pin which projects into elongated slot 43 of plate 41, and an aperture (not shown) in end plate 22 through which solid portion 47 passes. The bolt element 17 is normally spring biased toward the left in FIG. 1 by spring 71. When the element 17 is in single or snap latch position, pin 70 engages the left side of tab 57. When bolt element 17 is in its double latch or dead bolt position pin 70 engages the right edge of slot 43.

When bolt element 17 is in its single latch position as shown in FIG. 1, rotation of either of fingers 15 and 16 by rotation of their corresponding key plugs 12 or 13 in a clockwise direction causes said fingers to engage the right side of notch 45a in either plate 40 or 41 and thereby move bolt element 17 to a retracted position. Rotation of either of the fingers 15 or 16 in the counterclockwise direction by rotation of the corresponding key plug 12 or 13 causes the rotated finger to engage base 59 of member 56 and push member 56 upward so that tab 57 is moved out of engagement with pin 70 and bolt element 17 is moved rightward to its dead bolt position. When bolt element 17 is in its dead bolt position and either of finger 15 or 16 is rotated counterclockwise the bolt element is moved first to its single latch position by a single rotation of the finger and to a fully retracted position by a double rotation of the finger.

Knob operated finger means 19 is mounted for rotation to plate 21. Finger means 19 is spring biased counterclockwise by spring 72 which is connected between tab 73 and bracket 74. When bolt element 17 is in its single latch position as shown in FIG. 1, rotation of the knob (not shown) attached to finger means 19 in a counterclockwise direction (as viewed in FIG. 1) causes the finger 19 to engage element 56 secured in bolt element 17 and move bolt element 17 to the right to a retracted position as described above. When bolt element 17 is in its dead bolt position, knob operated finger means 19 is ineffective to move the bolt element since pin 70 and tab 57 cooperate to block movement. It should be..noted, of course, that when in the single latch position, spring 71 is stronger than spring 72 and retains the bolt element 17 as shown in FIG. 1.

Keeper mechanism generally designated 18 consists of a pin 80 slideably mounted for movement in hole 81 of bracket 74 in a direction transverse to the movement of bolt element 17. Projection 82 is rigidly connected to pin 80 and projects through elongated slot 83 in leaf spring 84 and elongated slot 85 in well 86 of end plate 22. Grip 87 is provided on projection 82 to retain it against the biasing of leaf spring 84. When bolt element 17 is in its retracted position, bore 88 in solid portion 47 is aligned with pin 80 and movement of grip 87 downwardly causes pin 80 to enter bore 83 and retain bolt element 17 in its retracted position against the biasing of spring 71.

Referring next to FIG. 5, there is shown an alternate embodiment of a locking mechanism of the instant invention. This embodiment is adapted for use in the rim lock mode of the cylinder lock described in applicant's above mentioned pending patent application. In this embodiment, cylinder housing 11 is the same as previously described and all of its parts bear the same reference numerals previously given. However, rather than a key plug being inserted in cylindrical bore 23a of upstanding portion 23, there is a plug 90 passing therethrough having finger means 91 on one end thereof and having a slot 92 for receipt of a bar 93 of a rim lock such as that above mentioned.

As can be seen from the above, a new and novel cylinder lock assembly has been provided which is operable by a key from either side of a door.

While the present invention has been described with respect to several preferred embodiments thereof, other embodiments within the spirit of the invention will now be obvious. it is therefore intended that the scope of the invention not be limited by the above illustrative disclosure but rather by the appended claims.

What is claimed is:

1. A locking mechanism operable by a key from either of two opposite sides of said mechanism for operating a bolt element comprising:

a first cylindrical housing:

a second cylindrical housing;

bridge means operatively connecting said first and second housings and forming a space therebetween;

first key plug means housed in said first housing and having a portion thereof extending into said space; first finger means mounted on said first key plug in said space for operation of said bolt element; second key plug means housed in said second housing and having a portion thereof extending into said space; second finger means mounted on said second key plug in said space for operation of said bolt element; and

an upstanding portion on said bridge means having a cylindrical aperture therethrough and one of said key plugs extending through said aperture with its finger means connected on the opposite side of said upstanding portion thereby connecting said bridge means to the cylindrical housing of said one ofsaid key plugs.

2. A locking mechanism as defined in claim 1 wherein said bridge means is integral with said second cylindrical housing and said upstanding portion connects said second cylindrical housing to said first cylindrical housing and defines a U-shaped space therebetween.

3. A locking mechanism as defined in claim 2 wherein said upstanding portion has the same cylindrical shape as said second cylindrical housing and said first cylindrical housing is of a different shape.

4. A locking mechanism as defined in claim 3 wherein said second cylindrical housing is shaped to accommodate a single row of tumbler holes and wherein said first cylindrical housing is shaped to accommodate a plurality of rows of tumbler holes.

5. A locking mechanism operable by a key from either of two opposite sides of said mechanism for operating a bolt element comprising:

a first cylindrical housing;

a second cylindrical housing;

bridge means operatively connecting said first and second housings and forming a space therebetween;

first key plug means housed in said first housing and having a portion thereof extending into said space; first finger means mounted on said first key plug in said space for operation of said bolt element; second key plug means housed in said second housing and having a portion thereof extending into said space; second finger means mounted on said second key plug in said space for operation of said bolt element;

at least one of said finger means consisting of a plurality of segments, each of said segments having an aperture therein which does not describe a complete circle and the aperture of at least one of said segments being angularly displaced from the apertures of the other segments;

at least one of said key plugs having its end shaped to correspond to the shape of said apertures in said segments whereby said segments may be placed on said end, and said key plug end having a groove therein at least as wide as said segment having said angularly displaced aperture whereby said segment having said angularly displaced aperture may be placed on said end of said key plug and rotated in said groove to a position aligned with said other segments;

and means fastening said segments together whereby said segments are fixed to said key plug.

6. The combination of a locking mechanism operable by a key from either of two opposite sides and an as- 5 sembly therefore, comprising:

a first cylindrical housing having a round crosssection to accommodate a plurality of rows of tumbler holes;

a second cylindrical housing having a cross-sectional configuration to accommodate a single row of tumbler holes;

bridge means operatively connecting said first and second housings and forming a U-shaped space therebetween;

first key plug means housed in said first housing and having a portion thereof extending into said U- shaped space;

first finger means mounted on said first key plug in said U-shaped space for operation of a bolt element;

second key plug means housed in said second housing and having a portion thereof extending into said U-shaped space;

second finger means mounted on said second key plug in said U-shaped space for operation of said bolt element;

a pair of parallel spaced assembly plates;

a bolt element mounted between said assembly plates and moveable by said first and second finger means between a plurality of positions;

a pair of aligned apertures in said assembly plates larger than said cross section of said second cylindrical housing whereby said second cylindrical housing may be passed through said assembly plates to position said U-shaped space between said assembly plates permitting said first and second finger means to be rotated for operation of said bolt element, said apertures in said assembly plates having the same configuration as said cross-section of said second cylindrical housing thereby preventing rotation of said second cylindrical housing with respect to said assembly plates;

and said first cylindrical housing having a plurality of threaded bores in its internal end, and one of said plates having a plurality of holes therein corresponding to said threaded bores and permitting said first cylindrical housing to be secured to said plate to prevent rotation of said first cylindrical housing with respect to said plate.

7. The combination defined in claim 6 wherein said first finger means is normally rotated to a position blocking the removal of said cylindrical housings from said plates when said key is not in said first key plug.

8. The combination of a locking mechanism operable by a key from either of two opposite sides and an assembly therefore comprising:

a first cylindrical housing;

a second cylindrical housing;

bridge means operatively connecting said first and second housings and forming a U-shaped space therebetween;

first key plug means housed in said first housing and having a portion thereof extending into said U- shaped space;

first finger means mounted on said first key plug in said U-shaped space for operation of a bolt element;

second key plug means housed in said second housing and having a portion thereof extending into said U-shaped space;

second finger means mounted on said second key plug in said U-shaped space for operation of said bolt element;

a pair of parallel spaced assembly plates;

a bolt element mounted between said assembly plates and slideable by said first and second finger means between three positions, a first retracted position, a second snap latch position and a third dead bolt position; said bolt element comprising a substantially solid portion having a bevelled strike camming surface for snap latch operation when in said second position, a pair of parallel bolt plates secured to said solid portion, at least one of said bolt plates having an elongated slot therein extending in the direction of movement of said bolt element; blocking means secured to one of said assembly plates extending through said elongated slot; spring biased means mounted between said bolt plates;

tab means on said spring biased means normally engaging said blocking means when said bolt element is in either said second or said third position thereby normally blocking movement of said bolt element between said second and third positions, said spring biased means being moveable by said first and second finger means to remove said tab means from engagement with said blocking means and thereby permit movement of said bolt element between said second and third positions by rotation of either of said key plugs; and

pair of aligned apertures in said assembly plates larger than a cross section of at least one of said cylindrical housings whereby said one of said cylindrical housings may be passed through said assembly plates to position said U-shaped space between said assembly plates permitting said first and second finger means to be rotated for operation of said bolt element.

9. The combination defined in claim 8 further including knob means mounted to one of said assembly plates and third finger means rotatable by said knob means for moving said bolt element between said first and second positions but being blocked from moving said bolt element between said second and third positions by engagement of said blocking means and said tab means.

10. The combination defined in claim 9 wherein said solid portion of said bolt element has a bore therein transverse to the movement of said bolt element; an end plate perpendicular to said assembly plates having a slot therein through which said solid portion moves; pin means mounted on one of said assembly plates; a second slot in said end plate; and projection means connected to said pin means and extending through said second slot in said end plate for enabling movement of said pin means into said bore in said solid portion of said bolt element when said bolt element is in said first position.

11. A locking mechanism operable by a key from either of two opposite sides of said mechanism for operating a bolt element, comprising;

a unitary member comprising a cylindrical housing and a bridge extending therefrom having an upstanding portion forming a U-shaped space;

key plug means housed in said cylindrical housing and having a portion thereof extending into said U- shaped space;

finger means mounted on said key plug in said U- shaped space for operation of said bolt element;

said upstanding portion having a bore passing therethrough;

cylindrical means extending through said bore and having a slot therein for mating with the rod of a rim lock and rotatable thereby; and

finger means mounted on said cylindrical means in said U-shaped space for operation of said bolt element.

12. A keeper mechanism for use in a latching assembly including a spring biased bolt normally biased to a position partially extending through an end plate, said keeper mechanism comprising:

9 10 a pin mounted in a bracket in said latching assembly of said pin when said bolt is in its retracted posifor movement transverse to the movement of said tion; and g bolt; a leaf spring between said end plate and said pin havtab means connected to said pin and extending ing an elongated slot therein through which said through an elongated slot in said end plate enabling 5 tab means passes, 'said leaf spring exerting a force said pin to be moved by said tab means in a direcon said pin retaining said pin in the position which tion transverse to the movement of said bolt; it has been moved. a bore in said bolt located in the path of movement 

1. A locking mechanism operable by a key from either of two opposite sides of said mechanism for operating a bolt element comprising: a first cylindrical housing: a second cylindrical housing; bridge means operatively connecting said first and second housings and forming a space therebetween; first key plug means housed in said first housing and having a portion thereof extending into said space; first finger means mounted on said first key plug in said space for operation of said bolt element; second key plug means housed in said second housing and having a portion thereof extending into said space; second finger means mounted on said second key plug in said space for operation of said bolt element; and an upstanding portion on said bridge means having a cylindrical aperture therethrough and one of said key plugs extending through said aperture with its finger means connected on the opposite side of said upstanding portion thereby connecting said bridge means to the cylindrical housing of said one of said key plugs.
 2. A locking mechanism as defined in claim 1 wherein said bridge means is integral with said second cylindrical housing and said upstanding portion connects said second cylindrical housing to said first cylindrical housing and defines a U-shaped space therebetween.
 3. A locking mechanism as defined in claim 2 wherein said upstanding portion has the same cylindrical shape as said second cylindrical housing and said first cylindrical housing is of a different shape.
 4. A locking mechanism as defined in claim 3 wherein said second cylindrical housing is shaped to accommodate a single row of tumbler holes and wherein said first cylindrical housing is shaped to accommodate a plurality of rows of tumbler holes.
 5. A locking mechanism operable by a key from either of two opposite sides of said mechanism for operating a bolt element comprising: a first cylindrical housing; a second cylindrical housing; bridge means operatively connecting said first and second housings and forming a space therebetween; first key plug means housed in said first housing and haVing a portion thereof extending into said space; first finger means mounted on said first key plug in said space for operation of said bolt element; second key plug means housed in said second housing and having a portion thereof extending into said space; second finger means mounted on said second key plug in said space for operation of said bolt element; at least one of said finger means consisting of a plurality of segments, each of said segments having an aperture therein which does not describe a complete circle and the aperture of at least one of said segments being angularly displaced from the apertures of the other segments; at least one of said key plugs having its end shaped to correspond to the shape of said apertures in said segments whereby said segments may be placed on said end, and said key plug end having a groove therein at least as wide as said segment having said angularly displaced aperture whereby said segment having said angularly displaced aperture may be placed on said end of said key plug and rotated in said groove to a position aligned with said other segments; and means fastening said segments together whereby said segments are fixed to said key plug.
 6. The combination of a locking mechanism operable by a key from either of two opposite sides and an assembly therefore, comprising: a first cylindrical housing having a round cross-section to accommodate a plurality of rows of tumbler holes; a second cylindrical housing having a cross-sectional configuration to accommodate a single row of tumbler holes; bridge means operatively connecting said first and second housings and forming a U-shaped space therebetween; first key plug means housed in said first housing and having a portion thereof extending into said U-shaped space; first finger means mounted on said first key plug in said U-shaped space for operation of a bolt element; second key plug means housed in said second housing and having a portion thereof extending into said U-shaped space; second finger means mounted on said second key plug in said U-shaped space for operation of said bolt element; a pair of parallel spaced assembly plates; a bolt element mounted between said assembly plates and moveable by said first and second finger means between a plurality of positions; a pair of aligned apertures in said assembly plates larger than said cross section of said second cylindrical housing whereby said second cylindrical housing may be passed through said assembly plates to position said U-shaped space between said assembly plates permitting said first and second finger means to be rotated for operation of said bolt element, said apertures in said assembly plates having the same configuration as said cross-section of said second cylindrical housing thereby preventing rotation of said second cylindrical housing with respect to said assembly plates; and said first cylindrical housing having a plurality of threaded bores in its internal end, and one of said plates having a plurality of holes therein corresponding to said threaded bores and permitting said first cylindrical housing to be secured to said plate to prevent rotation of said first cylindrical housing with respect to said plate.
 7. The combination defined in claim 6 wherein said first finger means is normally rotated to a position blocking the removal of said cylindrical housings from said plates when said key is not in said first key plug.
 8. The combination of a locking mechanism operable by a key from either of two opposite sides and an assembly therefore comprising: a first cylindrical housing; a second cylindrical housing; bridge means operatively connecting said first and second housings and forming a U-shaped space therebetween; first key plug means housed in said first housing and having a portion thereof extending into said U-shaped space; first finger means mounted on said first key plug in said U-shaped spAce for operation of a bolt element; second key plug means housed in said second housing and having a portion thereof extending into said U-shaped space; second finger means mounted on said second key plug in said U-shaped space for operation of said bolt element; a pair of parallel spaced assembly plates; a bolt element mounted between said assembly plates and slideable by said first and second finger means between three positions, a first retracted position, a second snap latch position and a third dead bolt position; said bolt element comprising a substantially solid portion having a bevelled strike camming surface for snap latch operation when in said second position, a pair of parallel bolt plates secured to said solid portion, at least one of said bolt plates having an elongated slot therein extending in the direction of movement of said bolt element; blocking means secured to one of said assembly plates extending through said elongated slot; spring biased means mounted between said bolt plates; tab means on said spring biased means normally engaging said blocking means when said bolt element is in either said second or said third position thereby normally blocking movement of said bolt element between said second and third positions, said spring biased means being moveable by said first and second finger means to remove said tab means from engagement with said blocking means and thereby permit movement of said bolt element between said second and third positions by rotation of either of said key plugs; and a pair of aligned apertures in said assembly plates larger than a cross section of at least one of said cylindrical housings whereby said one of said cylindrical housings may be passed through said assembly plates to position said U-shaped space between said assembly plates permitting said first and second finger means to be rotated for operation of said bolt element.
 9. The combination defined in claim 8 further including knob means mounted to one of said assembly plates and third finger means rotatable by said knob means for moving said bolt element between said first and second positions but being blocked from moving said bolt element between said second and third positions by engagement of said blocking means and said tab means.
 10. The combination defined in claim 9 wherein said solid portion of said bolt element has a bore therein transverse to the movement of said bolt element; an end plate perpendicular to said assembly plates having a slot therein through which said solid portion moves; pin means mounted on one of said assembly plates; a second slot in said end plate; and projection means connected to said pin means and extending through said second slot in said end plate for enabling movement of said pin means into said bore in said solid portion of said bolt element when said bolt element is in said first position.
 11. A locking mechanism operable by a key from either of two opposite sides of said mechanism for operating a bolt element, comprising; a unitary member comprising a cylindrical housing and a bridge extending therefrom having an upstanding portion forming a U-shaped space; key plug means housed in said cylindrical housing and having a portion thereof extending into said U-shaped space; finger means mounted on said key plug in said U-shaped space for operation of said bolt element; said upstanding portion having a bore passing therethrough; cylindrical means extending through said bore and having a slot therein for mating with the rod of a rim lock and rotatable thereby; and finger means mounted on said cylindrical means in said U-shaped space for operation of said bolt element.
 12. A keeper mechanism for use in a latching assembly including a spring biased bolt normally biased to a position partially extending through an end plate, said keeper mechanism comprising: a pin mounted in a bracket in said latching assembly for movement transverse to the moveMent of said bolt; tab means connected to said pin and extending through an elongated slot in said end plate enabling said pin to be moved by said tab means in a direction transverse to the movement of said bolt; a bore in said bolt located in the path of movement of said pin when said bolt is in its retracted position; and a leaf spring between said end plate and said pin having an elongated slot therein through which said tab means passes, said leaf spring exerting a force on said pin retaining said pin in the position which it has been moved. 